There was a mix of news about the Gulf of Maine last week. First, there were dire warnings about the role of rising ocean temperatures in the demise of cod in the North Atlantic. Then came what sounded like good news — Maine has surpassed Massachusetts to become the state with the second most lucrative seafood landings in the country. Finally, on Friday, federal regulators announced they would close the Gulf of Maine herring fishery this month.

All of these stories are interrelated and point to the need for much more research to gain better understanding about what is happening in the Atlantic Ocean and why. With better knowledge about how changing ocean conditions affect different species, regulators can more effectively target rules to protect them and the fishermen who make a living catching them.

The virtual disappearance of cod from the waters off New England is not news. But a new report, published in the journal Science, concludes that rising ocean temperatures played a much larger role in the decline than initially thought.The study’s lead author, Andrew Pershing, is a scientist with the Gulf of Maine Research Institute in Portland.

In the simplest sense, regulators decide how many tons of a species can be taken from the ocean based on assessments of that species’ population. The problem with cod management, Pershing’s report concludes, is that regulators didn’t fully grasp the severity of the ocean temperature increase and what it meant for the legendary groundfish. As a result, regulators allowed fishermen to catch too many cod.

“Failure to recognize the impact of warming on cod contributed to overfishing,” the report said. “Recovery of this fishery depends on sound management, but the size of the stock depends on future temperature conditions. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management.”

This is especially true in the gulf, which is warming faster than 99.9 percent of the world’s oceans. Most troubling, beginning in 2004, the rate of warming in the Gulf of Maine increased more than seven-fold, the report says. Because of this rapid warming, regulatory limits on cod fishing didn’t work because cod did not reproduce and grow as expected.

This isn’t an academic problem. As the cod population declined, regulators imposed quotas that allowed fishermen to catch less. When the population didn’t rebound, regulators tightened the quotas, adding to the economic hardship for fishing communities.

This situation is repeating itself with herring, a popular bait fish. Because fishermen have already caught more than 90 percent of the allowable herring catch in the inshore zone of the Gulf of Maine, the National Marine Fisheries Service stopped the herring season on Monday. The season began Oct. 1 and was set to run until Dec. 31.

Massachusetts slipped from the No. 2 spot in the nation in terms of the value of its fishery because of the decline in the cod catch. Alaska remains No. 1. Dockside landings in Massachusetts were worth $524.7 million in 2014, down from $566.8 million in 2013, according to the 2014 Fisheries of the United States report.

Bolstered by a rise in the lobster catch, the value of Maine’s landings rose to $547.6 million last year from $473.8 million in 2013.

Cod are a major lobster predator, so the warming ocean appears to benefit lobster — for now. As the report in Science warns, this may not continue and regulators, with the help of fishermen and scientists, need to closely monitor ocean conditions to know if and when changes are affecting lobster and other sea life — preferably before their numbers dwindle.

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The BDN Editorial Board

The Bangor Daily News editorial board members are Publisher Richard J. Warren, Opinion Editor Susan Young, Deputy Opinion Editor Matt Junker and BDN President Todd Benoit. Young has worked for the BDN...